This invention is a medical device. More specifically, it is a balloon catheter having a lumen with a port proximal of a balloon through which therapeutic or diagnostic agents may be delivered.
Balloon Catheter Overview
Balloon catheters are medical devices that have been used to facilitate percutaneous medical treatment such as pressure monitoring, cardiac output and flow monitoring, angioplasty, artificial vaso-occlusion, and cardiac support. Balloon catheters generally have an elongated shaft with a fluid expandable balloon on the distal end and a coupler on the proximal end. Balloon catheter designs generally include a lumen that extends from the coupler end to the balloon end and facilitates delivery of fluid therethrough for inflating the balloon. One way that balloon catheters may be classified is by the way they are adapted for delivery into remote in-vivo sites. Among such balloon catheter categories are xe2x80x9cflow-directed,xe2x80x9d xe2x80x9cover-the-wire,xe2x80x9d xe2x80x9cfixed-wire,xe2x80x9d and xe2x80x9csingle-lumenxe2x80x9d balloon catheters.
xe2x80x9cFlow-directedxe2x80x9d balloon catheters are generally balloon catheters in which the balloon is inflated at a low pressure and acts like a sail in the blood stream. The inflated balloon, along with the attached catheter, is pulled downstream to a remote location by the blood flow acting on the inflated balloon.
xe2x80x9cOver-the-wirexe2x80x9d balloon catheters are generally balloon catheters that slideably track over an independent wire rail to a distally remote location. Generally, a radiopaque, steerable guide wire may be negotiated, via radiographic visualization, to a desired remote location such as a distal site in the vascular tree. Over-the-wire catheters generally have two lumens. A first lumen, the guide wire lumen, is used for slidably receiving and tracking over a steerable guide wire. The guide wire lumen often extends substantially the full length of the catheter and terminates at each end in open ports. Alternatively, the guide wire lumen may extend only between a distal port and a proximal port that is situated on the catheter distally of the catheter""s proximal end. The second lumen terminates at a distal end in a sealed, expandable balloon, and at the opposite proximal end in an open port. The proximal open end may be coupled with a pressurizable fluid source for inflating and deflating the balloon.
When a guide wire lumen extends the length of the catheter and the proximal port is accessible to a doctor during in-vivo use, there is a benefit in being able to exchange multiple wires slideably through the guide wire lumen. The balloon catheter is kept in place as a conduit delivery device for such guide wire exchangesxe2x80x94the wires do not need to be re-steered and tracked to the desired site each time. Also, this full length co-axial arrangement between catheter and wire allows manipulation of the wire""s placement during balloon inflation. This may be desirable, for instance, for seating the wire in a side vessel distal to the balloon inflation site to retain access thereto in the case the vasculature distal to the inflation site collapses during the artificial total occlusion created by the balloon.
In contrast to the features just described, over-the-wire catheters may alternatively have the guide wire lumen extend only along a distal portion of the catheter length, with the proximal guide wire port disposed distally to the catheter proximal end. With this type of over-the-wire design, a shortened length of catheter rides co-axially on the wire. As such, a much shorter wire may be used (compared to full length co-axial over-the-wire designs) and still facilitate the exchangability of the catheter over the wire. However, the proximal guide wire port in such designs is generally disposed within the body spaces during in-vivo use. This often renders guide wire exchanges through the guide wire lumen quite difficult and often impossible while the distal positioning of such catheters is maintained.
xe2x80x9cFixed-wirexe2x80x9d balloon catheters have a steerable guide wire integrated into the balloon catheter assembly. In this way, the balloon catheter and guide wire may be advanced into distal anatomy as a unit. The guide wire may be torqued to cause a rotational response at the tip; although, in fixed wire catheters the guide wire is somewhat restrained in the limits of its movement such that it is not truly independent of the catheter. For example, the guide wire in a fixed wire balloon catheter usually may not be advanced or retracted axially and has a limit in the number of rotating turns that can be imparted to the wire relative to the catheter.
A single lumen may be provided in fixed wire balloon catheters, serving the function both as a balloon inflation lumen and a guide wire lumen. This provides a more modest profile when compared with multilumen catheter designs. In order to effectuate balloon inflation in a fixed wire balloon design having only a single lumen, the distal end of the balloon is sealed onto the wire. This may be accomplished either by affixing the balloon to the wire or by limiting the clearance between the wire and the balloon.
More recent balloon catheter designs are generally referred to as xe2x80x9csingle-lumenxe2x80x9d catheters. Such single lumen catheters may include a guide wire that is independent of the catheter. The single lumen of xe2x80x9csingle lumenxe2x80x9d catheters facilitates balloon inflation and at the same time is co-axial with the guide wire, as is generally the case in many fixed wire balloon catheter designs. However, this embodiment of the xe2x80x9csingle lumenxe2x80x9d balloon catheter often has a valve mechanism provided on the catheter (or on the wire) such that a fluid seal may be selectively achieved between the wire and the catheter. Thus, the wire is slidable within the lumen and may be advanced and torqued relatively independently of the catheter in order to select and track to remote sites. Yet, the lumen may be tightly sealed onto the wire via the valve mechanism provided for balloon inflation when desired.
One example of a single lumen balloon catheter having a valve situated on the guide wire for effecting a seal at the balloon catheter tip is found in U.S. Pat. No. 5,304,198 to Samson, et al. Samson discloses a single-lumen balloon catheter having a valve seat on the distal end of the catheter, distal of the balloon, which may be operated by a control wire having a valve plug disposed on the wire. The valve seat may be engaged by the valve plug from either direction, depending on the installation of the control wire. Pushing or pulling on the wire, depending on the initial orientation of the wire relative to the valve seat, will seat the valve plug in the valve seat and allow the introduction of fluid through the catheter lumen to inflate the balloon.
Other examples of balloon catheters that generally have one lumen that is coaxially disposed about the guide wire and is also used for balloon inflation are disclosed in the following references: U.S. Pat. No. 5,171,221 to Samson; U.S. Pat. No. 4,606,347 to Fogarty, et al.; U.S. Pat. No. 5,085,636 to Burns; U.S. Pat. No. 4,813,934 to Engelson, et al.; and U.S. Pat. No. 5,437,632 to Engelson, et al.
Delivery Catheter Overview
Although balloon catheters may facilitate medical treatment by providing a fluid expandable balloon on a distal portion thereof, delivery catheters facilitate medical treatment by providing a conduit with one or more distal ports for remote delivery of diagnostic or therapeutic agents. Such agents may be fluids, such as drugs or radiopaque dyes, or devices, such as wires or vaso-occlusive coils.
Delivery catheters are often delivered to remote in-vivo locations in a manner similar to that used for over-the-wire balloon catheters. A steerable guide wire is extended to a point at or near the desired treatment site. Delivery catheters are usually provided with a lumen that allows the delivery catheter to co-axially track over the wire to the desired site.
For xe2x80x9cend holexe2x80x9d delivery catheters, agents such as fluids may be delivered out a distal end port provided. Fluid agents may be so delivered either through the co-axial space between the catheter and the wire or through the open lumen with the wire removed.
One example of a delivery catheter having an end hole port for fluid delivery is disclosed in U.S. Pat. No. 4,739,768 to Engelson. Engelson discloses a catheter which can be guided over a guide wire along a tortuous path of at least about 5 cm through vessels of less than about 3 mm lumen inner diameter. Engelson further discloses delivery of fluid materials through a lumen provided after the guide wire is withdrawn. The fluid materials may include radio-opaque agents, vaso-occlusive agents, such as a suspension of collagen fibers, which can be used to produce small-artery vaso-occlusion, and pharmacological agents.
Alternatively or in addition to end holes for such fluid or device delivery, xe2x80x9cside holexe2x80x9d delivery catheters may have one or more ports near to and proximal of the catheter distal end. These ports may be in fluid communication either with a single lumen or with more than one lumen. These multiple distal ports are often in a desired spatial arrangement, such as at a predetermined spaced interval longitudinally along the catheter axis, in a spiral arrangement, etc.
Balloon/Delivery Catheter Overview
Some medical conditions may require both a balloon catheter and a fluid delivery catheter to facilitate treatment. For instance, a patient may need a balloon inflation for performing angioplasty to re-open blocked vessels. Simultaneous or serial delivery of drugs such as thrombolytic agents, or of radiopaque dye for visualization, may be desirable at the angioplasty site. Or, a patient treatment may require fluid communication through a distal catheter port, which port may be desirably isolated from certain flow dynamics, such as from branching vessels other than a targetted vessel. This may be desirable for instance for isolated drug delivery out the port and only into a targetted side branch vessel, or for radiopaque dye delivery into that side branch.
In part to provide solutions to these needs, catheters have been disclosed having a fluid delivery port adjacent the balloon such that the balloon may be inflated against a vessel wall to isolate the delivery site from hemodynamics opposite the balloon from the port. Such a port may be located distally of the balloon. Such isolation may be accompolished in a guide wire lumen in the general over-the-wire balloon catheter designs. Additionally, balloon catheters have been disclosed having lumens ending in side ports disposed proximally of the balloon catheter. Balloon catheters of the types just described may be generally referred to as xe2x80x9cballoon/deliveryxe2x80x9d catheters, although particular references may use different descriptors.
One example of a dilation-drug delivery catheter is disclosed in U.S. Pat. No. 5,415,636 to Forman. Forman describes a dilation-drug delivery catheter having a dilation portion for dilating a stenosis and a drug delivery portion for delivering antithrombolytic, antiproliferative, or any other type of medication to the dilation site. The drug delivery portion of the catheter is located within the dilation portion, which can be retracted to reveal the drug delivery portion distal thereto after dilation. occlusion balloons described in the reference are preferably provided on the drug delivery portion to isolate the dilation site during drug delivery. A dilatation lumen, a drug delivery lumen, a guide wire lumen, and an inflation lumen in an inner catheter shaft are provided in the catheter described.
Another example of a balloon catheter having a proximal port connected to a lumen is disclosed in U.S. Pat. No. 5,413,581 to Goy. Goy discloses a balloon dilatation catheter having a first lumen extending along the entire length of a shaft, which lumen is connected to a pump and, at the distal end of the catheter, to the inside of the balloon. Through this lumen there also passes a support wire connected firmly to the catheter at the catheter""s distal end. The shaft has an additional lumen which opens outwards of the catheter via an opening behind the proximal end of the balloon. Goy discloses that a controllable guide wire can be introduced into this additional lumen via an attachment piece, and that a measuring apparatus or an apparatus for introducing a contrast medium or drug can as well be connected to this additional lumen.
Another dilatation balloon catheter having an infusion lumen is found in U.S. Pat. No. 5,368,567 to Lee. Lee discloses a dilatation catheter having two or more associated fluid carrying tubes, the operative or distal end of one of which supplies fluid to inflate an expansible balloon and the operable or distal end of the other of which supplies an injectable dye or contrast enhancing fluid adjacent the proximal end of the balloon. The catheter embodiments disclosed by Lee also include a guide wire lumen separate from the balloon inflation lumen. The proximal end of the short guide wire lumen preferably begins adjacent the distal opening of a hollow tube lumen for injecting contrast medium proximal of the balloon. The distal end of the short guide wire lumen terminates distally of the sealed balloon.
U.S. Pat. No. 4,983,166 to Yamawaki discloses a balloon catheter having a balloon and a main passage ending in an opening behind the balloon. The reference discloses that, with the balloon inflated, drugs may be delivered through the opening and into other branches than that in which the balloon catheter tip is placed. Yamawaki discloses use of a circulatory curved tip end portion of the balloon catheter for inserting the catheter from a thicker artery into a thinner artery diverging from the thicker artery at an acute angle. The reference further discloses that a guidewire may be placed in the drug delivery passageway and out the opening behind the balloon, but does not otherwise disclose a guidewire lumen for tracking of the catheter over a guidewire to a remote in-vivo location.
None of these references disclose a balloon/delivery catheter having a single lumen for both balloon inflation and guide wire tracking, and having a second lumen for delivery of therapeutic or diagnostic agents to and out a delivery port proximal to the balloon.
Vaso-Occlusion Agents and Delivery Techniques
One example of a medical treatment that has, for certain applications, been facilitated by delivery of therapeutic treatments through balloon/delivery catheters is artificial vaso-occlusion.
Artificial vaso-occlusion or embolization is a medical treatment that often involves locally delivering an agent to a desired site. The agent therein causes a physiological occlusive response to flow or otherwise blocks or fills a body space. Different sites in the body where vaso-occlusion treatments have been used include aneurysms, blood vessels, and arterio-venous malformations.
Accurate placement during the delivery of vaso-occlusive agents is critical, since inaccurate placement of the occlusive device may undesirably occlude regions were continued flow must or should be maintained. Appropriate placement is especially important where an agent is relatively fluid and may migrate from the desired site if exposed to physiological flow. It is at least in part for this reason that it is often desirable to isolate target delivery sites from flow dynamics of adjacent vasculature when delivering vaso-occlusive agents.
Examples of various chemicals that have been used for in-vivo artificial vaso-occlusion include ethanol, estrogen, polyvinyl acetate (xe2x80x9cPVAxe2x80x9d), ethylene vinyl alcohol (xe2x80x9cEVALxe2x80x9d), cellulose acetate polymer, or combinations thereof. Known delivery techniques for such vaso-occlusive agents include delivery through microcatheter-type delivery catheters, and delivery through balloon/delivery catheters having delivery ports distal to expandable balloons.
One reference to arterial embolization through a balloon catheter with a passage ending in an opening proximal of the balloon is in U.S. Pat. No. 4,983,166 to Yamawaki (introduced above). However, as mentioned above, Yamawaki does not disclose a means for tracking the balloon catheter over a guidewire to a remote site, but instead uses a circulatory curved tip for subselectivity of side branches.
Another example of an embolization treatment via balloon catheter delivery of chemical embolizing agents in the renal arteries is disclosed in xe2x80x9cNonsurgical Treatment of AVM: Development of New Liquid Embolization Method,xe2x80x9d Takahashi, et al., Suzuki J., ed., Advances in surgery for cerebral stroke, Tokyo, Japan: Springer-Verlag 1988:215-224. Takahashi discloses percutaneous delivery of conjugated estrogen diluted in 25% ethanol and polyvinyl acetate (xe2x80x9cPVacxe2x80x9d). According to the disclosure, PVac, when diluted in alcohol, becomes gelatinous in one second upon contacting water. Disclosed treatment methods included injections of PVac during proximal occlusion using slow leaking double lumen balloon catheters after 20 minute infusion of alcohol.
Other documents that disclose examples of balloon catheter aided chemical delivery techniques for artificial vaso-occlusion include: xe2x80x9cExperimental Investigations Concerning a New Liquid Embolization Method: Combined Administration of Ethanol-estrogen and Polyvinyl Acetatexe2x80x9d by Sugawara, et al., Neurol Med Chir (Tokyo) 33,71-76, 1993; xe2x80x9cA New Liquid Material for Embolization of Arteriovenous Malformationsxe2x80x9d by Taki, et al., AJNR 11:163-168, January/February 1990; xe2x80x9cDirect thrombosis of aneurysms with cellulose acetate polymer (Part I: Results of thrombosis in experimental aneurysms)xe2x80x9d by Mandai, M.D., et al., J Neurosurg 77;497-500, 1992.
None of these references discloses delivery of a vaso-occlusive agent through a lumen proximally of a balloon in a catheter assembly that is trackable to a remote in-vivo site over a guidewire. There is a need for such a balloon/delivery catheter for achieving isolated vaso-occlusive agent delivery in tortuous anatomy where distal migration of the delivered agent is not desired. There is also a need for a balloon/delivery catheter having a single lumen for facilitating balloon inflation and guide wire tracking and having a second lumen ending in a port proximal to the balloon for delivery of diagnostic and therapeutic agents.
This invention is a medical catheter that comprises a body having on its distal end portion an expandable balloon. An inflation/wire lumen extends between a port on the proximal portion of the catheter and a distal guide wire port located distal to the balloon. The inflation/wire lumen is also fluidly coupled to the balloon. At least one delivery lumen also extends from the proximal end portion of the body and has a delivery port located proximal to the balloon. The delivery port provides for fluid communication between the delivery lumen and external body spaces.
In one embodiment of the invention, a wire with a valve plug is slidably disposed within the inflation/ wire lumen to form an adjustable pressure seal at a valve seat on the distal end of the catheter. This wire allows fluid within the guidewire/inflation lumen to be pressurized by a pressurisable fluid source in order to effectuate balloon inflation.
In another embodiment of the invention, a vaso-occlusive agent delivery assembly is provided having a balloon/delivery catheter with an expandable balloon on a distal end portion fluidly coupled to a proximal pressure source, a guidewire lumen with a guidewire port distal of the balloon, and a delivery lumen with a delivery port proximal of the balloon for delivering a vaso-occlusive agent. The assembly further comprises a pressurizable vaso-occlusive agent source coupled to a proximal port of the delivery lumen such that a vaso-occlusive agent may be delivered through the delivery lumen and out the delivery port proximally of the expanded balloon. In one variation of this embodiment, the balloon/delivery catheter of the vaso-occlusive agent delivery assembly may comprise a single inflation/wire lumen that is both fluidly coupled to the balloon and adapted to co-axially receive a guidewire. In another variation of the embodiment, the assembly includes a guidewire co-axially coupled into the balloon catheter""s guidewire lumen.
Also contemplated as a part of the present invention are preferred methods of use of the embodiments described.